Vinsen Faris has watched many volunteers come and go during his 16 years with Meals On Wheels of Johnson and Ellis Counties in Texas. But even he was surprised last week when eight volunteers left for the same reason: the high cost of filling their tanks to deliver meals to homebound seniors.

"Until now we've never had people call up and specifically say, 'I'm having to drop out because of the price of gas,' " says Mr. Faris, executive director. "I think it's sticker shock. They fill up and say, 'Wow, I just paid $2 a gallon.' "

Across the country, other Meals On Wheels sites are reporting similar experiences. Although the number of departing volunteers is small and scattered, the losses illustrate one way higher fuel prices are affecting social-service organizations and those who help them.

Nationwide, Meals On Wheels and other programs provide meals to approximately 1 million homebound older people every day. In many cases, the meal is the only nutritious food the recipient will get that day. Some programs serve 30 to 40 meals daily, while others feed 3,000. Some are small and rural and rely on volunteers. Others serve urban and suburban areas and pay drivers modest wages. The vast majority use volunteer drivers.

For many recipients, the Monday-through-Friday deliveries of two meals a day also provide another form of nourishment - brief companionship, conversation, and concern for their well-being.

Faris calls the drivers "our eyes and our ears" because of their daily visits. In a majority of cases, he explains, they are the homebound person's only contact with the outside world.

Many volunteer drivers for meal programs are retired and live on fixed incomes. "Their heart may still want them to be out on the route, but their pocketbook prevents them from being there," says Peggy Ingraham, a director for the Meals On Wheels Association of America in Alexandria, Va.

One longtime driver concerned about the spike at the pumps is Nace Emorey, who earns $7.50 an hour delivering for Senior Meals On Wheels of Kent County, Mich. He puts 600 miles a week on his car and buys his own gasoline.

"If we lose Nace, we're in big trouble," says Linda Quist, associate director. "He drives a rural route. He not only delivers the meals, he brings their newspaper in and brings their mail in for them. He changes their thermostat and opens and closes their windows."

Along with the added out-of-pocket expenses that Mr. Emorey and volunteers are absorbing, groups that provide senior meals are spending more to operate their own vehicles, reducing the funds available for meals.

In Austin, Texas, Meals On Wheels and More cooks 2,000 meals a day in a central kitchen, and then transfers them in a fleet of vans to 15 sites - such as churches and senior centers - where volunteers pick them up. Higher gas prices have increased operating costs.

In Pocatello, the Southeast Idaho Community Action Agency Meals On Wheels is spending $200 more a month for gas. And in Waterbury, Conn., a Meals On Wheels program, New Opportunities Inc., expects to overspend its fuel budget by more than $15,000 by the end of September.

"It's devastating," says Ms. Ingraham. "How many meals could have been purchased with that money?" Nationally, the average cost of a meal - food and delivery - is $5.

Rising fuel prices come at a time when federal funding for senior meal programs is "absolutely flat," Ingraham says. At the same time, the need for meals is increasing. Those 85 and over, who may require help to stay in their homes, constitute the fastest-growing demographic group in the country.

Last week Ms. Quist, in Grand Rapids, Mich., had to submit her 2005 budget request for federal and state funding. "How can I guess what gas is going to go up to, and how that's going to impact food?" she asks. Already milk has gone up by 23 percent in her area. Her program uses 500 quarts a week.

Allen Jefferis, a board member of Meals On Wheels Greater San Diego, which is doing well, has been delivering meals for eight years. When gasoline prices went up several years ago, he recalls, many volunteers left the program. He expects those who stayed to weather this increase.

Although some meal programs are being forced to suspend delivery routes, others make sure that even when volunteers leave, recipients will not go hungry. "When we don't have enough volunteers, the staff delivers," says Michael Goldstein, a spokesman for the Austin program. "We just work longer hours."

Other workers adopt a similar can-do attitude.

"Most of our volunteers say, 'I just tighten my belt a little bit, because delivering meals is so important,' " Mr. Goldstein notes. Last week a volunteer told him, "I've been doing this for 11 years. I'm not going to stop just because gas prices have gone up. Instead I don't drink as many Starbucks coffees anymore."

Faris is similarly optimistic. "We're going to get through this," he says. "It's a bump in the road. It's a tough time for us, but it's going to be OK."